Method of assembling a transmission

ABSTRACT

This transmission has multiratio drive planetary gearing and a plurality of fluid actuators for selectively engaging a plurality of friction devices to engage the ratio drives. A central web splined to the transmission housing has oppositely facing fluid actuators each having an annular piston in a cylinder. Each piston has an inner annular engagement seat and an outer interrupted annular engagement seat for engaging the brake plates with retraction springs and fastener posts located between the seats. A retainer plate has an annular portion between the seats engaging the springs and an aperture fitting on the retainer posts and has and has ear portions extending into engagement with the web. Snap rings hold the retainer plates and web against axial movement. A fastener on the fastener post holds the retainer plate and springs in assembled position for assembly into the transmission.

I United States Patent [151 3,653,118 Koivunen [451 Apr. 4, 1972 [54] METHOD OF ASSEMBLING A 3,429,021 2/1969 Spiess ..29/434 x TRANSMISSION 3,579,803 5/1971 Lautenschlager ..29/434 [72] Inventor: Erkki Koivunen, Livonia, Mich. primary Examine, wayne Morse, [73] Assignee: General Motors Corporation, Detroit, Fmken and 57 ABSTRACT 'I t. l, 1970 [22] F1 ed Sep 2 This transmission has multiratio drive planetary gearing and a [2]] Appl. No.: 74,023 plurality of fluid actuators for selectively engaging a plurality Related US. Application Data of friction devices to engage the ratio drives. A central web splined to the transmission housing has oppositely facing fluid [62] Division of 832 168 June 11, 1969 Pat No. actuators each having an annular piston in a cylinder. Each 3 596 537. y piston has an inner annular engagement seat and an outer interrupted annular engagement seat for engaging the brake 52 US. Cl ..29/434 29/226 29/467 Plates with relractim Springs and fastener P05S Owed [51] Intel I B23, 19/04 B23q 7 B2g41/08 between the seats. A retainer plate has an annular portion [58] Field 29/429 467 226 between the seats engaging the springs and an aperture fitting 'i on the retainer posts and has and has ear portions extending [56] References Cited into engagement with the web. Snap rings hold the retainer plates and web against axial movement. A fastener on the UNITED STATES PATENTS fastener post holds the retainer plate and springs in assembled position for assembly into the transmission. 3,115,699 12/1963 Nakahira ..29/226 3,186,081 6/1965 Barisch ..29/434 5 Claims, 3 Drawing Figures W 84' W 124 w W mt i z I [2Z5] Z 4'5 w. i 148 154 a i a 4 w l. I 135 58 88 I27 a V w I42 1 i 66 I 6 93 45 5052 I 1I l 115 132 32 L140 52 I 1 72 r J 58 h a 7, a u f 7nd L I z m 105 1o 15 m METHOD OF ASSEMBLING A TRANSMISSION This is a Division of Ser. No. 832,168 filed June 11, 1969 now US. Pat. No. 3,596,537 issued Aug. 3, 1971.

This invention relates to transmissions and particularly to an improved fluid actuated ratio establishing friction device and bearing support structure for gearing providing simplified assembly and an improved method of assembly.

Transmission constructions which require assembly of many complex parts on different splines, the use of many snap rings and the compression of the retraction springs for the pistons of the fluid actuators during assembly of the transmission parts in the housing present a difflcult and expensive assembly opera tion.

Transmissions, in addition to meeting the drive requirements of the vehicle in which they are used, should have a simple structural support arrangement which can be easily assembled to insure uniform assembly for reliability and reduction of initial and repair costs. In accordance with this invention the number and complexity of the parts is reduced, particularly the number of snap rings and the fluid actuator devices and their retraction springs which are preassembled with the springs compressed to facilitate transmission assembly.

The object of the invention is to provide an improved transmission to facilitate and simplify assembly.

Another object of this invention is to provide a fluid actuator preassembly having a movable actuator member with a retainer member secured to said movable actuator member only to prevent separating movement to hold the retraction springs between these members and permit apply movement in the final assembly.

Another object of the invention is to provide an improved fluid actuator in which the piston is located in the cylinder and retraction springs are precompressed between the piston and the retraction plate which is secured to the piston by a fastener to hold the retraction springs compressed but which permits apply movement during fluid operation of the fluid actuator.

Another object of the invention is to provide an improved method of assembling a transmission in which the retraction springs are placed on the movable actuator member and a retainer plate is attached to the movable actuator member to prevent only separating movement to hold the springs in position to provide a preassembly for positioning in a fixed actuator member.

Another object of this invention is to provide improved fluid actuator and friction device components of a transmission to facilitate assembly into a transmission housing.

These and other objects and advantages will be apparent to those skilled in the art from the following description and drawings.

FIG. 1 shows a partial cross section of the transmission gearing and fluid actuated friction devices.

FIG. 2 is a section on line 22 of FIG. 1 showing details of the fluid actuator.

FIG. 3 is an exploded view of the fluid actuator.

DESCRIPTION OF THE DRAWINGS Referring to FIG. 1, there is a transmission having a housing which enclosed a torque converter, a hydraulic pump not shown but fully described in application, Ser. No. 805,190 Power Transmission, filed Mar. 7, 1969 by John J. OMalley and showing three planetary gear sets 16, 18 and 20.

A torque converter of conventional construction transmits power from the engine to the transmission gearing through input shaft 36 splined to a clutch housing 38. The clutch housing 38 is drivingly connected to two input clutches 40 and 42.

The input clutch 40 includes a plurality of alternately spaced plates 44 and 46 which are splined to the clutch housing 38 and a hub 48 respectively. A piston 50 is slidably mounted in a fluid chamber 52 in the clutch housing 38. The fluid pressure in chamber 52 urges the piston 50 to engage the clutch plates 44 and 46 to the clutch 40. The return spring 54 is held in compression between the piston 50 and a spring retainer 56 which is mounted on the housing 38. The return spring 54 moves the piston 50 out of engagement with the clutch plate when the chamber 52 is not pressurized. A passage 58 in the housing 38 is adapted to supply fluid to the chamber 52.

The clutch 42 includes a plurality of alternately spaced plates 60 and 62 which are splined to the clutch housing 38 and to a drum 64 respectively. A piston 66 is slidably mounted in chamber 68 in drum 64. The chamber is pressurized to engage the clutch 42. A passage 70 in drum 64 conveys fluid pressure to chamber 68. A return spring 72 is compressed between the piston 66 and a spring retainer 74 mounted on drum 64 and functions to move the piston out of engagement when the chamber 68 is not pressurized. A brake 76 is also operatively connected with the drum 64 and includes alternately spaced plates 78 splined to the drum 64 and plates having four or more sets of spaced pairs of teeth 80' extending from the outer perimeter which fit in four or more spaced pairs of spline recesses 90. The splines 90 are axially short and only extend from 90' to 90", the length of the clutch plates 78-80 snap ring 91, backing plate 75 and snap ring 77, so the case may be cast with a one piece core and axially drawn. The draft in these short splines does not provide excessive clearance at the thin or front ends. The web 84 is rotatably fixed by fittings, such as fitting 94' for line 94 and axially located between snap rings 91 and 93 in grooves in the transmission housing 10. The fitting 94 is shown at the top of the housing for convenience but is usually at the bottom adjacent the valve body not shown. A piston or movable actuator member 82 is slidably mounted in the annular chamber or cylinder 86 having annular sidewalls and a transverse wall formed in the central web 84. When chamber 86 in the fixed actuator or web is filled with pressure fluid piston 82 moves to engage the brake 76.

The plates of brake 76 are located between the fixed backing or abutment plate 75 located by snap ring 77 in a groove in splines 90 and housing 10 and the annular actuator apply face on inner actuator annulus 79 and the interrupted annular face or outer actuator annulus 81 both on piston 82. The outer actuator annulus 81 has gaps therein for cars 87" of retainer plate 87. Fastener posts 83 are fixed or integral with the transverse wall of the piston or movable actuator between the annuluses providing the apply faces. The transverse wall has a fluid confining face facing in the direction into the cylinder.

A plurality of coil return springs 88 seated in round pockets 85 between annuluses 79 and 81 engage the annular spring retainer plate 87 which is fixed in a groove 84' in the fixed actuator or central web 84 and retained therein by wedge snap ring 91 to bias the piston out of engagement with the plates 78 and 80 when the brake is disengaged. Note that retainer plate 87 has an annular portion 87 between the inner and outer actuator annuluses 79 and 81 engaged by the springs 88 and anchoring ear portions 87" extending through the interruptions or gaps between the parts of the interrupted annular outer actuator portion to seat in the groove 84' in web 84. Openings or holes 87a in the retainer plate 87 fit over posts 83 to guide and locate the retainer plate with respect to the piston 82.

The friction fastener 89 slips on the post 83 and holds the piston 82 and retainer plate 87 at a fixed maximum distance apart with the retraction springs 88 preferably partially compressed and almost in the fully retracted position. This subassembly remains as assembled during transmission assembly and disassembly. When the transmission is assembled as pointed out below, the wedge snap ring 91 moves the retainer plate 87 sufficiently to relieve the spring load on fastener 89. The springs and posts are symmetrically distributed about the annulus to provide a balanced retraction force and load on the attachable fastener means, post 83 and fastener 89.

The central web 84 is rotatably secured to the transmission housing by fittings, i.e., fitting 94' and has a plurality of fluid passages 92, 94 and 96 which are adaptive to supply pressure to the clutch 42, the brake 76 and brake 98 respectively as shown in detail in the above Ser. No. 805,190.

Brake 98 has plates 122-124 abutting the fixed abutment plate 125 which is axially positioned by the step 1235 in spline recess 123. The plates 124 have a plurality of pairs of cars 124 and the abutment plate 125 has similar ears 125' which fit in the spline recesses 123 arranged in a plurality of pairs about the perimeter. The short spline 123 from end 123' to end 123" has minimum draft to avoid excessive clearance in the forward splines. As shown in FIG. 2, a clearance recess 223 extends forwardly in the housing between spline recesses 90 so the rear plates can be assembled from the open front of the transmission housing and so this long recess can have maximum draft. This access recess is generally wider than both spline recesses. Thus web 84 is piloted by the cylindrical internal diameter of the housing which is only interrupted by recesses 223.

Piston 126 is like piston 82 with springs 130 seated in round holes or seating pockets 127 between the inner engagement seat 129 and the outer interrupted annular engagement seat 131. The annular retainer 133 has an annular portion 135 engaging springs 130 and ears 137 extending between the portions of the interrupted engagement seat 131 into a groove in web 84 and retained therein by snap ring 93. As in piston 82, piston 126 has a fastener post between each group of retainer springs extending through an opening in the annular portion of the retainer ring and a fastener to hold the retainer plate and springs in assembled position. The web 84 also provides rotational support for an intermediate sleeve shaft 104 which is splined to the drum 64 and for an intermediate shaft 106 which is splined to the hub 48 and rotatably journalled in the sleeve shaft 104.

The sleeve shaft 104 is splined to a pair of sun gears 108 and 110 which are components of the planetary gear sets 16 and 18 respectively. The planetary gear set 16 also includes a plurality of planet pinions l 12 which are rotatably mounted in a carrier 114 and mesh with the sun gear 108 and a ring gear 1 16 which is drivingly connected to a carrier 118 of the planetary gear set 18 and a carrier 120 which is a member of the planetary gear set 20. The carrier 114 is operatively connected to the brake 98 which includes the plurality of alternately spaced plates 122 and 124 which are splined to the carrier 114 and the housing respectively. The piston 126 is slidably mounted in annular cylinder or chamber 128 in the central web 84. The chamber 128 is filled with pressure fluid via passage 96 to engage the brake 98. A plurality of return springs 130 are provided to move the piston 126 out of engagement with the brake plates 122-124 to disengage the brake 98 when the chamber 128 is not pressurized.

The planetary set 18 includes a plurality of pinion gears 132 which are rotatably mounted on the carrier 1 l8 and mesh with the sun gear 110 and a ring gear 134 which is drivingly connected through a hub 136 with a sun gear 138 of the planetary set 20. The ring gear 134 and the sun gear 138 are splined to the intermediate shaft 106 which is connected to the input clutch 40.

The planetary set also includes a plurality of pinion gears 140 which are rotatably mounted on the carrier 120 and mesh with the sun gear 138 and a ring gear 142. The carrier 120, the carrier 118 and the ring gear 116 are drivingly connected to the transmission output shaft 144. The ring gear 142 is operatively connected to a brake 146 which includes a plurality of alternately spaced plates 148 and 150 which are splined to the splines 151 in the transmission housing 10 and the ring gear 142 respectively. The splines 151 are cast axially draftable splines at a smaller diameter than splines 90 and so the housing is an axially draftable casting. A piston 152 is slidably disposed in chamber 154 in the transmission housing 10. When apply chamber 154 is filled with pressure fluid, the piston 152 engages the plates 148-150 thereby applying the brake 146. A plurality of return springs (not shown) are provided to move the piston 152 out of engagement with the brake plates when the chamber 154 is not pressurized.

Rotation of pistons 84 and 126 may be prevented by pins 161 set in bores in web 84 and fitting recesses 162 in cars 87" of spring retainer 87 which engages the piston 82 at the edge of ears 87" fitting in the gaps between the portions of interrupted actuator annulus 81 or at the aperture 87a for post 83. Also half circular abutments 163 and 164 or an abutment and fitting recess on the web 84 and piston 82 may prevent rotation of the piston.

The clutches and brakes described above are actuated by fluid pressure in the manner described in the above Ser. No. 805,190.

The clutch 40, when engaged, provides a drive connection from the torque converter or input to the sun gear 138 and ring gear 134. The clutch 42, when engaged, provides a drive connection from the torque converter or input to the sun gears 108 and 110. The brake 76, when engaged, restrains the sun gears 108 and from rotation to thereby establish sun gear 110 as a reaction member. Brake 98 restrains carrier 1 14 from rotation and thereby establishes the carrier as a reaction member. The brake 146 restrains the ring gear 142 from rotation and thereby establishes the ring gear as a reaction member. To provide first gear drive forward, the clutch 40 and the brake 146 are engaged thus providing a simple planetary reduction in the planetary gear set 20.

To establish second gear forward, the brake 146 is disengaged while the brake 98 is engaged and the clutch 40 remains engaged to provide a compound reduction drive in planetary gear sets 18 and 16 between the input shaft 34 and the output shaft 144. In second gear forward, the ring gear 134 is the input member for the planetary gearing and ring gear 116 and carrier 118 are output members. The planetary set 20 merely idles and carries no load.

To establish third gear forward, the brake 98 is disengaged while the brake 76 is engaged and the clutch 40 remains engaged thus providing a simple planetary reduction in planetary gear set 18 between the input shaft 34 and the output shaft 144. The ring gear 134 is also the input member in third gear forward and the carrier 1 18 is the output member.

To establish fourth gear forward, the brake 76 is disengaged while the clutch 42 is engaged and the clutch 40 remains engaged. With both clutches 40 and 42 engaged, the planetary sets 16, 18 and 20 are in a lockup or one-to-one condition thus providing a direct drive from the input shaft 34 to the output shaft 144.

To establish one reverse ratio, the clutch 42 is engaged and the brake 146 is engaged. This provides a compound reverse reduction ratio in planetary gear sets 18 and 20 between the input shaft 34 and the output shaft 144. In this reverse drive, the sun gear 1 10 is the input member and the carrier is the output member for the planetary gear sets.

To establish another reverse ratio, the brake 146 is disengaged while the brake 98 is engaged and the clutch 42 remains engaged. This establishes a simple planetary reverse reduction drive in planetary gear set 16 between the input shaft 34 and the output shaft 144. In this drive, the sun gear 108 is the input member and the ring gear 116 is the output member of the planetary gear set.

This transmission structure facilitates manual or automatic assembly of the transmission. The piston or movable actuator member 82 is preassembled with the springs 88 and retainer plate 87 and secured by fastener 89. This preassembly is made by inserting springs 88 in the spring pockets 85 which hold the springs in place. Then the retainer plate is placed in position to be moved between the annuluses 79 and 81 with the cars 87'' in the gaps in outer annulus 81 by aligning holes 87a with posts 83 and moving the retainer plate toward the piston and compressing the springs until the retainer plate is below the actuator faces. Then the fastener is placed on the post to hold the preassembly together with the springs having the desired degree of precompression and ready to move or be further compressed in the actuating stroke when assembled with the cylinder or fixed actuating member. Then this piston preassembly is placed in the cylinder until the piston bottoms on the cylinder at stop portions 82' on the piston and cylinder and the cars 87'' on the retainer plate partially enter the groove 84 at the free end of the annular wall of cylinder 86 to hold the piston in the fully retracted position of its operating stroke. Then piston 126, springs 130 and retainer plate 133 are similarly assembled and inserted in cylinder 128.

Then the transmission parts are assembled through the front open end of housing 10. The piston 152, which may be an assembly like piston 82 is inserted in chamber 154 and the plates 148,150 and backing member are placed in the rear splines and secured by a snap ring. Then the gear unit is assembled in position. Then the backing plate 126 is placed on splines 123 against stop shoulder 1238 and plates 122-124 are placed on these splines against the backing plate. The snap ring 93 is then inserted. The preassembled web 84 and pistons 82 and 126 are then inserted with the ears of retainer plate 133 engaging ring 93. The wedge snap ring 91 is inserted and engages the web and retains the ears of retainer plate 87 so both retainer plates are retained with a small clearance in the grooves in the web. This movement of the retainer plates toward each other by the wedge snap ring compresses the retraction springs a small additional amount to provide a small clearance between the fasteners and the retainer rings to relieve the load on the fasteners 89 when they are thus assembled in the housing. Note that the wedge snap ring 91 has a bottom clearance so regardless of tolerance variations, it seats on and holds the web against ring 93. The web seats in a pilot bore through which the recesses 223 extend and is secured against rotation by fittings 94'. The friction plates 78, 80 and backing plate 75 are then assembled in the splines and located by snap ring 77. Then the clutch assemblies 42 and 38 are inserted in the housing.

Each of spline recesses 90, 123 and 151 are short axially draftable splines which have a small minimum draft. The long draft of access recess 223 for the rear spline is merely an access recess and has as large a draft as desired. The rear splines are short and at a smaller diameter. Thus rear splines, central splines and front splines with a pilot diameter between the central and front splines may be cast with an axially draftable core.

It should be understood that the above description is of an exemplary embodiment and that obvious modifications will occur to those skilled in the art.

It is claimed:

1. In a method of assembling a transmission; the steps of preassembling a movable actuator member, retraction springs, a retainer plate and fastening the retainer plate to the movable actuator member to limit only expansion movement of the retraction springs to provide a preassembled unit with the springs almost in the fully retracted position; inserting said preassembled unit with the movable actuator member slidably assembled in a fixed actuator member and locating said retainer plate closely adjacent a positioning means on said fixed actuator member and fastening said retainer plate against said positioning means on said fixed actuator member to locate said retainer plate and said movable actuator member in the fully retracted position with respect to said fixed actuator member with the springs in the fully retracted position so the fastener does not limit expansion movement of the retraction springs and permits operating movement of the movable actuator member.

2. The invention defined in claim 1 and inserting a fixed actuator member in the internal splines of the housing against an axial abutment; and fastening both said fixed actuator member and retainer plate against said positioning means with a single securing ring.

3. In a method of assembling a transmission; the steps of preassembling a movable actuator member and a retainer plate with retraction springs therebetween and fastening the retainer plate to the movable actuator member to limit only separating movement of the movable actuator member and retainer plate and thus expansion movement of the retraction springs while permitting approaching movement of the movable actuator member and retainer plate and thus contraction movement of the retraction springs to provide a preassembled unit with the springs movable actuator member and retainer plate relatively positioned in a retracted position; inserting said preassembled unit with the movable actuator member slidably assembled on a fixed actuator and locating said retainer plate against a positioning means on a said fixed actuator and fastening said retainer plate against said positioning means on said fixed actuator to locate said retainer plate and said movable actuator member in a retracted position in said fixed actuator member with the springs in a retracted position so the fastener does not prevent compression of the retraction springs during operating movement of the movable actuator member.

4. The invention defined in claim 3 and in the step of preassembling said preassembled unit fastening said retainer plate to the movable actuator member to contain said springs in a preassembly retracted position and in the steps of locating and fastening said retainer plate with the movable actuator on the fixed actuator engaging the movable actuator against the fixed actuator to further compress the springs to a fully retracted position relieving spring expansion force on the fastener and permitting further compression of said springs during operating movement of said movable actuator member.

5. The invention defined in claim 4 and inserting said fixed actuator member in the internal splines of a housing against an axial abutment and inserting a single fastening ring in a groove in the splines to hold said retainer plate against the positioning means on the fixed actuator and the fixed actuator against the abutment to hold the complete assembly in operating position. 

1. In a method of assembling a transmission; the steps of preassembling a movable actuator member, retraction springs, a retainer plate and fastening the retainer plate to the movable actuator member to limit only expansion movement of the retraction springs to provide a preassembled unit with the springs almost in the fully retracted position; inserting said preassembled unit with the movable actuator member slidably assembled in a fixed actuator member and locating said retainer plate closely adjacent a positioning means on said fixed actuator member and fastening said retainer plate against said positioning means on said fixed actuator member to locate said retainer plate and said movable actuator member in the fully retracted position with respect to said fixed actuator member with the springs in the fully retracted position so the fastener does not limit expansion movement of the retraction springs and permits operating movement of the movable actuator member.
 2. The invention defined in claim 1 and inserting a fixed actuator member in the internal splines of the housing against an axial abutment; and fastening both said fixed actuator member and retainer plate against said positioning means with a single securing ring.
 3. In a method of assembling a transmission; the steps of preassembling a movable actuator member and a retainer plate with retraction springs therebetween and fastening the retainer plate to the movable actuator member to limit only separating movement of the movable actuator member and retainer plate and thus expansion movement of the retraction springs while permitting approaching movement of the movable actuator member and retainer plate and thus contraction movement of the retraction springs to provide a preassembled unit with the springs, movable actuator member and retainer plate relatively positioned in a retracted position; inserting said preassembled unit with the movable actuator member slidably assembled on a fixed actuator and locating said retainer plate against a positioning means on a said fixed actuator and fastening said retainer plate against said positioning means on said fixed actuator to locate said retainer plate and said movable actuator member in a retracted position in said fixed actuator member with the springs in a retracted position so the fastener does not prevent compression of the retraction springs during operating movement of the movable actuator member.
 4. The invention defined in claim 3 and in the step of preassembling said preassembled unit fastening said retainer plate to the movable actuator member to contain said springs in a preassembly retracted position and in the steps of locating and fastening said retainer plate with the movable actuator on the fixed actuator engaging the movable actuator against the fixed actuator to further compress the springs to a fully retracted position relieving spring expansion force on the fastener and permitting further compression of said springs during operating movement of said movable actuator member.
 5. The invention defined in claim 4 and inserting said fixed actuator member in the internal splines of a Housing against an axial abutment and inserting a single fastening ring in a groove in the splines to hold said retainer plate against the positioning means on the fixed actuator and the fixed actuator against the abutment to hold the complete assembly in operating position. 